Not to worry, for Google's apparently got you covered even then. If you subscribe to YouTube Red you might actually receive a Chromecast for free, courtesy of Google. The company has started sending out an email to some YouTube Red subscribers letting them know that they can claim a free Chromecast, by way of a special link to the Google store. This link is part of the email you receive, so clicking it will take you to the store, where you choose your desired color for the Chromecast and that's it.

Note that this may not go out to all YouTube Red subscribers, since Google hasn't officially announced the promotion. That said, several people have already received the aforementioned email, so it clearly isn't a one-off thing either. Considering that the Chromecast is priced at $35, this isn't an earth-shattering freebie, but it's a nice gesture from Google regardless.